Joshua Green at The Atlantic has a piece on the “Tragedy of Sarah Palin”, which you can read here. In essence, his point seems to be she was willing to work with Democrats when she was Governor of Alaska, and yet now, and ever since her debut at the Republican convention, she has seemed uncompromisingly conservative. Green thinks this change was very bad for her political career.
Read the article for yourself, but my opinion is that there never was a change; Sarah Palin talked like an anti-elitist populist when she ran for governor, and she talked like an anti-elitist populist when she spoke at the Republican convention. What changed was that earlier her populism was directed at multinational businesses and greedy politicians who sold out to them. When she reached the national stage, she directed it towards the intellectuals.